A couple of devices I know of...no practical experience with them to report, though.
Stewart warner used to sell a device called the Electrovac...they turn up at the fleas, and I have a couple. Small vac pump with pressure drop switch, an electric motor about the size of a heater motor spins the thing.
Smart 1940's economics, there...save the cost of electric motor by using vac wipers, then add electric motor to supply more vacuum...
1980's GM hardware, probably exists in other lines...Corvettes and small-engined X cars got a electric vac pump with switch to keep brake booster happy when engine was running at a low vac level...one switch plugged into a hole in booster, which would require some adapting to make it workable for us, a few had an inline switch in the vac hose leading to electric pump, which would be easier to adapt to a wiper system. This stuff could be hooked to a can...remember that in the modern cars, the brake booster canister served as a reservoir.
Typically, the electric pump lived under the battery. Hidden in a fender in Corvettes... the systems can be spotted by the existence of 2 rather than 1 big hose on the brake booster, and of course following the hosiery will lead you to the electric stuff.
I also saw one junked Cadillac, one of the troublesome aluminum V8 ones, that had a mechanical vac pump with a little pump like a smog pump driven by a tiny auxiliary belt off the engine. This stuff should still be findable and dirt cheap. Interesting science experiment for anyone with 12 volts...